I have a ten gallon heavy planted tank with four oto cats and nine neon tetras and now we have two bettas in bowls. I would love to set up a tank for them, partitioned with black acrylic so they couldn't see each other, but things being what they are another tank is out of the question for now. I would like to put one betta in the ten with the cats and neons but don't know if the bettas would kill the neons or the neons would shred the bettas fins. Anyone have first hand experience with them together please let me know.
Tanks in advance

Some Bettas are so aggressive they do not want any other fish in their tank, especially as small as a 10 gallon tank.
Other Bettas are pretty cool with other species, as long as the other fish stay lower in the tank.

Try one of the Bettas in the 10 with the Neons. WATCH it. If the Betta does not like the situation, try the other Betta.

Not a good idea to try partitioning the 10.

Most Neons are not nippers, but this is not a guarantee that there never have been any neons that ever nipped. Again, WATCH it. If you see the Neons pestering the Betta, then put the Betta back in his original bowl, and try to make these bowls the best possible homes for them. Perhaps try to plan for a bigger tank (at least a 5 gallon, but even an Eclipse 3 would be a nicer home for a Betta than a bowl.